from tkinter import *

paint_run = False

def paint(event):
	if paint_run:
		c.create_oval(event.x-5, event.y-5, event.x+5, event.y+5, fill = 'black')

def run(event):
	global paint_run
	if paint_run:
		paint_run = False
	else:
		paint_run = True


root = Tk()
root.resizable(width = False, height = False)
root.geometry('500x500')
root.title('MyPaint')

c = Canvas(width = 500, height = 500, bg = 'white')
c.focus_set()
c.pack()

root.bind('<Motion>', paint)
root.bind('<Button-1>', run)

root.mainloop()